1. Field of the Invention
The present invention relates to a process of management of a thermochemical reaction or of a solid-gas adsorption permitting the production of cold and/or of heat.
2. Description of the Related Art
A thermochemical reaction, or an adsorption, is based on a reversible reaction between a solid and a gas, and can be schematized by the equation: ##STR1##
In the reactor, the reaction is exothermic in the direction 1, which means that it produces heat, and it is endothermic in the direction 2. In the direction 1, it likewise produces cold in the associated evaporator by the evaporation of the gas (G).
Such a system permits the storage of energy in a chemical or physical form, and has varied fields of application.
In a conventional manner, this type of thermochemical or adsorption reaction is located in a system comprising an enclosure, termed a "reactor", containing a salt or an adsorbent and, preferably, an expanded binder which is a good conductor of heat. The reactor is arranged so as to be capable of being selectively placed in communication with a second enclosure forming an evaporator/condenser assembly for the gas intended to react with the salt. This communication is effected by a duct provided with a control valve. During a conventional cycle of reaction or of adsorption, the valve is open, permitting the gas present in liquid form in the evaporator to be evaporated and to pass through the duct in order to react with the salt or the adsorbent present in the reactor, resulting in the cooling of the evaporator. At the end of the evaporation phase, the salt or the adsorbent in the reactor is heated, for example by means of an electrical resistance, thus causing the discharge of the gas toward the condenser. The control valve permits stopping the reaction cycle at any moment.
In order to permit a continuous production of cold and/or of heat, two analogous sub-assemblies can be placed side by side, one producing cold and/or heat while the other is in a regeneration phase.
An example of a thermochemical system of this type, having two sub-assemblies, is described in the document EP-A-0 382 586. In this system, the evaporator/condenser assembly of each sub-assembly comprises a reactor able to absorb or desorb the gas. The ducts connecting the reactors are each provided with a control valve for the passage of gas. The control valves form the sole means of setting in operation or of stopping the thermochemical reaction or the adsorption/desorption.
The use of control valves in the ducts connecting the reactors has two disadvantages.
Each valve requires an associated actuation for opening or closing it, and this increases the cost and/or the complexity of the system. But in addition, the presence of valves increases the risk of leaks of gas from the system. This risk of leaks of gas, for example of ammonia, reduces the number of practical applications of this type of thermochemical system.